In extreme position slide switch assembly with auxiliary switch deactivated by controller

ABSTRACT

The specification discloses a miniaturized multi-position slide switch adapted for low voltage, low current applications, for example, so-called &#39;&#39;&#39;&#39;shirt pocket&#39;&#39;&#39;&#39; electronic calculators employing printed circuitry. Switch control elements of uniform configuration are arranged in a row in facing pairs in an insulating base, while an insulating cover for the base carries a track for a sliding contactor having a spring-biased steel ball. The base has a central longitudinal groove of V-shaped cross section in which the steel ball rides. Detenting is accomplished by a declining bevel or ramp connecting the V-groove to the Vshaped seat formed between the pairs of switch contact elements. One of the pairs of contact elements has a connector biased into normally closed contact therewith. At one extremity of its travel, the sliding contactor engages the connector and disengages it from contact with the contact elements. A dust shield in the form of an endless tape longitudinally surrounds the base and cover and has an opening through which the handle of the sliding contactor extends. The tape shield is thus shifted in an endless path by shifting of the sliding contactor.

Umted States Patent 1 In 3,757,060 Ianuzzi et al. 1 Sept. 4, 1973 SLIDE SWITCH ASSEMBLY WITH AUXILIARY SWITCI-I DEACTIVATED BY 57 S RAC CONTROLLER IN EXTREME POSITION The specification discloses a miniaturized multi- Inventors! J P lalllllli, Vestal; Donald position slide switch adapted for low voltage, low cury, Afton, both of rent applications, for example, so-called shirt pocket [73] Assign: The Union Corporation, Verona, electronic calculators employing printed circuitry. Switch control elements of uniform configuration are Filed! Jlllle 1972 arranged in a row in facing pairs in an insulating base, while an insulating cover for the base carries a track for [21] Appl' No" 262097 a sliding contactor having a spring-biased steel ball. The base has a central longitudinal groove of V-shaped Zoo/16 200/166 Zoo/168 G cross section-in which the steel ball rides. Detenting is [51] Int. Cl. "01h 15/02, H0111 9/04 accomplished by a declining bevel or ramp connecting Field of Search 16 16 16 the V-groove to the V-shaped seat formed between the ZOO/DIG 166 168 G pairs of switch contact elements. One of the pairs of contact elements has a connector biased into normally References Cited closed contact therewith. At one extremity of its travel,

UNITED STATES PATENTS the sliding contactor engages the connector and disen- 3,l87,l 19 6/1965 Dyksterhouse 200/16 c gages mm with f f A dust 3 55 3/1967 Hemiksen shield m the form of an endless tape longitudinally sur- 3,582,573 6/1971 L k d rounds the base and cover and has an opening through 3,643,042 2/1972 Gratz..... which the handle of the sliding contactor extends. The 3,43l,374 4/ 1969 Raab 200/16 C X tape shield is thus shifted in an endless path by shifting Primary Examiner-J. R. Scott Atlorney-Buell, Blenko & Ziesenheim of the sliding contactor.

13 Claims, 12 Drawing Figures 3 I m a 5 4- 1 7 I I /37 42 43 45o /39 lo 53 5| l5 |s |7 52 45 1 44 34 |3 sa I I i J YA V as a 1. I4 1 I I 27 33 t 2 PATENTEDSEP 4191s SHEET 1 BF 2 PAIENIEU 4W5 3.757.060

SHEET 2 OF 2 Flg ll Handle SWITCH CONTACT Position Elements 3| I O O O 0 O 2 O O O X X 3 O O X 0 X 4 O X 0 0 X 5 X 0 O O X 0- Open X- Closed SLIDE SWITCH ASSEMBLY WITH AUXILIARY SWITCH DEACTIVATED BY CONTROLLER IN EXTREME POSITION This invention relates to a miniaturized multiposition slide switch capable of use with various types of applications employing printed circuitry and of low voltage and low current rating.

Multi-position switches having a sliding contactor have been heretofore known and employed for various purposes. However, because of their large size and relatively high voltage and current rating, known type slide switches are not suitable for certain applications, such as the so-called shirt pocket electronic calculators.

It is the object of this invention, therefore, to provide a miniaturized slide switch of appropriately small size and low voltage and current rating for use in various types of applications employing printed circuitry.

We provide a miniaturized slide switch having a multiple number of positions, including a number of normally open switch positions and at least one normally closed switch position.

We further provide a miniaturized slide switch in which contact elements of uniform size and contour are disposed in opposingly faced pairs to provide a multiple of switch positions. A spring-biased steel ball carried in a sliding handle moves in a V-groove of a base from position to position, detenting being accomplished by a bevel or ramp between the V-groove and the space be tween opposingly faced contactele ments.

We further provide a normally closed switch contact arrangement comprising a steel ball biased into seated contact with a pair of opposingly faced contact elements by a leaf spring element and unseated laterally by engagement of a projection on the slide contactor therewith at an extremity of travel, the ball moving up the ramp on the base to disconnect the contact elements. Alternatively, a spring connector of S-shape provides the normally closed connection, the slide contactor engaging the connector at its extremity of travel to open the switch connection.

We further provide a dust shield for the switch contacts, the shield comprising an endless tape having an opening through which the handle of the slide contactor extends, and the movement of the handle shifting the tape in an endless path in surrounding sealed relation to the base and cover of the switch body.

Further details of the above features are set forth hereinafter in a full description of a preferred embodiment of slide switch shown in the accompanying drawings, wherein:

F IG. 1 is a plan view of the preferred'form of miniaturized slide switch embodying the invention, on greatly enlarged scale;

FIG. 2 is an elevational sectional view taken on the line ll-ll of FIG; 1;

FIG. 3 is a transverse sectional view, taken substantially on the line Ill-III of FIG. 2;

FIG. 4 is a plan view of the cover of the switch body, on the same scale as shown in FIG. 2;

FIGS. 5 and 6 are transverse sectional views taken respectively on the lines V-V and Vl---Vl of FIG. 4;

FIG. 7 is a plan view of the base of the switch body, with the cover removed therefrom, in the same scale as shown in FIG. 2;

FIGS. 8, 9 and 10 are transverse sectional views, taken respectively on lines VIII-Vlll, IXIX and XX of FIG. 7;

FIG. 11 is a chart indicating the open or closed condition of the switch contacts in the various positions of the handle of the sliding contactor; and

FIG. 12 is a fragmental plan view of a modified form of base embodying a different form of normally closed switch.

Referring to the drawings, the embodiment of slide switch 10 shown comprises a switch body including a base element 11, hereinafter called the base and a cooperating cover element 12, herafter called the cover. Both the base and the cover are made of suitable insulating plastic or resinous composition, molded to appropriate size, length and contour. As constructed, the parts are of such dimensions as to result in an overall length of the switch 10 of 0.95 inch, a width of 0.375 inch and a thickness of about 0.3 inch.

As will be seen in FIGS. 2 and 3, the cover 12 and base 11 are correspondingly rectangular in shape. Cover 12 has a rectangular recess 13 in its lower face into which an upper portion of the base 11 snugly fits. The bottom of the outside wall of the cover 12 seats on a flat shoulder 14 surrounding the upper portion of base 1 l.

Referring to FIGS. 2, 4, 5 and 6, it will be noted that the upper face of the cover 12 has a rectangular recess 15, which in'cooperation with recess 13 at the bottom forms a central partition 16. In partition 16 is a longitudinally extending rectangular slot 17 surrounded by a rectangular flat shoulder 18 on the upper surface of partition 16.

Referring to FIGS. 7, 8, 9 and 10, it will be noted that the upper portion of base 11 is formed with a rectangular recess 19, at the bottom of which is a flat intermediate plateau or surface 20. Extending inwardly from the bottom face of base 11 is a longitudinal slot or recess 21, which is separated from the recess 19 by a partition 22 of substantial thickness. Formed in the partition 22, coincident with the longitudinal center line of surface 20, is a groove 23 of V-shape in cross-section, which extends substantially the full length of the recess 19.

As seen particularly in FIGS. 7 and 8, the surface 20 of the partition 22 has a plurality of transverse slots 24 formed therein shown illustratively as five in number, which intersect the V-groove 23 at substantially a right angle. Slots 24 are uniformly spaced longitudinally with the exception of the two slots 24 at the right-hand end of the switch 10, as viewed in FIG. 7. Interposed between the two last mentioned slots .24 is a relatively short enlarged section 25 of the V groove 23. On each side of the four left-hand transverse slots 24, at the intersection with the V-groove 23 is a bevel or ramp 26. A similar bevel 26' is interposed at the intersection of V-groove 23 and the lefthand side of enlarged V- section 25. On the right-hand side of the slot 24 atthe right-hand end of switch 10 is a so-called ramp 27.

The opposite ends of the slots 24 are intersected by rectangular holes 28 which open at the lower face of the base 11. The central portion of the slots 24 is also recessed at 29, as seen in FIG. 8, slightly below the V- groove 23.

Inserted in each of the holes 28 is a contact element 31" made preferably of brass, in the form of a flat ribbon with a re-entrant portion or hook at one end. The contact elements 31 are all uniform and are inserted in the holes 28 so that the hooked ends face each other opposingly, as clearly shown in FIG. 3, the ends of the hooks extending down into the recessed portion 29 of the slot 24. There is thus formed within each slot 24 between the hooked ends of each pair of contact elements 31 a substantially V-shaped recess.

Seated normally in contact with the pair of contact elements 31 at the right-hand end of the switch is a corrosion resistant steel ball 33 which is yieldingly biased into contact with the contact elements 31 by a leaf spring 34 loosely secured in the base 1 1 above the ball.

For cooperation with certain of the contact elements 31, a slide contactor 35 is provided. Contactor 35 comprises a rectangular body portion 36 which is of approximately the same thickness as the depth of recess in the cover 12, in which it is adapted to slide reciprocatively. A tubular extension 37 on the upper side of the body portion provides a handle by which to grasp the contactor and slide it to different switching positions, as hereinafter described.

Projecting downwardly from the bottom of the body portion 36 is a longitudinal rib 38 of a substantially V- shaped cross-section, the apex of the rib extending downwardly through the slot 17 in the cover in registry with the V-groove 23.

Formed within the tubular extension or handle 37 is a circular hole or bore 39 which also extends down through the body 36 and opens through the rib 38. Contained in the bore 39 is a pair of corrosion resistant steel balls 40, the lower of which is loosely held at the lower end of a tubular cartridge member 41, which in turn has a sliding fit within the bore 39.

A helical spring 43 is interposed in the bore 39 between the upper most ball 40 in the cartridge member 41 and a plug element 42 that is secured in the outer end of bore 39 as by cementing, thus causing the lower one of the balls 40 to be resiliently biased downwardly into contact with the pairs of contact elements 31 in certain of the switching positions, as hereafter described. The plug element 42 preferably has a polygonal contour, shown as square, at its outer end which fits in a conforming recess at the outer end of bore 39. The use of two balls in the cartridge 41 insures that the lower ball 40 moves freely in the cartridge for detenting purposes. It is of course possible to use a single ball but our experience indicates that there is a possibility of a single ball hanging up.

The base 11 is constructed so as to support five pairs of cooperating or opposingly faced contact elements 31, arranged in substantially uniformly spaced axial positions, except for the two pairs of contact elements 31 at the right-hand end of switch 10, as viewed in FIG. 2. The spacing between these two pairs of contact elements 31 is substantially twice that between the other pairs of contact elements but the enlarged section 25 of V-groove 23 is substantially midway therebetween. Thus, the lower steel ball 40 of the contactor 35 is yieldingly biased successively into contact with the four pairs of contact elements 31 in each of four switch positions as the contactor 35 is moved in the right-hand direction from its left-hand extremity of travel. These switch positions are successively designated 5, 4, 3 and 2, as indicated in FIG. 2. As the contactor 35 is shifted further in the right-hand direction from position 2, the lower steel ball 40 is biased or detented into the enlarged section 25 of V-groove 23. in this position of the contactor 35, referred to as switch position 1, a projection 44 on the right-hand end of the lower V-shap'ed rib portion 38 of the body of the contactor 35 engages the steel ball 33 and shifts it toward the right up the ramp 27 against the yielding force of leaf spring 34, thereby effecting disengagement of ball 33 from the contact elements 31. Upon restoration of contactor 35 to switch position 2, the spring 34 causes the steel ball 33 to be snapped down the ramp 27 into a circuit-closing position in contact with the contact elements 31.

An alternative base 1 1 may be provided as shown in FIG. 12, in which a different arrangement is employed for providing the normally closed contacts in switch position I. In this arrangement, there is provided in lieu of the steel ball 33 and leaf spring 34 a spring element 33 of S-shape. The spring element 33' is interposed edgewise between the pair of contact elements 31 and the end wall of a recess 19'. Recess 19' is somewhat longer than recess 19 of base 11 and ramp 27 is omitted in order to provide room to accommodate spring element 33. As will be apparent in FIG. 12, one leg of spring element 33 maintains normal bridging contact with the contact elements 31. When the slide contactor 35 reaches switch position 1, however, the projection 44 engages the switch contact bridging leg of spring element 33' and disengages the spring element from briding relation to contact elements 31, thus opening the switch. When the contactor is shifted to the left out of switch position 1, the leg of spring element 33 resiliently returns to closed position in bridging relation to the contact elements 31.

Referring to the chart in FIG. 11, the connected or disconnected condition of the contact elements 31 in the different switch positions 1 through 5 is shown, the connected condition being designated closed and indicated by the symbol X and the disconnected condition being designated open and indicated by the symbol O. The pairs of contact elements 31 are arranged in the same order in the chart as that in which they are shown in FIG. 2.

A dust shield, in the form of a flat ribbon or tape 45 fixed to the contactor 35 by anchor means 45a, serves to keep the contact elements 31 covered in all positions of the contactor 35. As will be apparent in FIGS. 1, 2 and 3, the tape 45 has a square opening 46 therein through which the handle of the contactor 35 projects. The tape 45, which is cemented or otherwise adhesively fastened together at its ends into an endless loop, seats in a pair of aligned grooves 46 (FIGS. 4 and 7) formed at the opposite ends of the base 11' and cover 12 and in the top face of the cover 12 adjacent opposite ends thereof. As previously described, the lower portion of the base 11 has a longitudinally extending slot 21, through which the return portion of the endless loop tape 45 passes. The tape 45 is maintained taut, that is tensioned, by means of a cantilevered leaf spring 48 of shallow V-shape. One end of spring 48 is loosely anchored in a transverse slot 49 (FIG. 10) in the bottom of slot 21, while the other rounded end engages the bottom surface of the slot 21 in base 11. The apex of the V-spring 48 faces downwardly and engages the inner face of the dust shield tape 45. Thus, as the contactor handle shifts to the different switch positions, the tape is maintained taut against the top and end surfaces of the cover 12 and base 11, and effectively seals the cover against the entry of dust and dirt into the recess 15 through which to settle on and contaminate the contact elements 31 and the steel balls 33 and 40.

The base ill and cover 12 are maintained in tightfitting engagement by a sheet-metal shroud or cover 51 of relatively thin gauge (e.g. 0.020 inch) which serves also for mounting purposes. The cover 51 is preferably formed by stamping in one piece, to provide a rectangular slot 52, narrower in width than the tape 45, through which the contactor handle extends. Cover 51 also has holes 53 at opposite ends through which to insert attaching nails orscrews, and tabs 54 designed to be bent at right angles into corresponding slots or recesses 55 (FIGS. 2 and 3) in the bottom of the base 11. Also four legs 56, one at each corner of the switch cover 51, serve for mounting and attaching the switch in a panel board. For this purpose a shoulder 57 is provided in each leg to fix the relation between the panel board and the switch, while the ends of the legs 56 may be bent at right angles to hold the switch in position.

It will be observed that with the switch 10 mounted in position, the projecting ribbon-like ends of contact elements 31 are desirably positioned for connection in printed circuitry, as by soldering.

The manner of operation of the slide switch 10 should be apparent from the foregoing description. While the positions of the contactor handle are not shown marked on the cover 51, they may be if desired. However, by reason of the detenting arrangement including the lower steel ball 40 of contactor 35 which snaps quickly out of the V-groove 23 in which it rolls or slides into contact with the opposingly faced hooked ends of contact elements 31, the different switch positions 2 to 5 may be readily sensed by contact of the thumb or finger on the contactor handle. Similarly, when the lower ball 40 snaps out of the V-groove 23 into the larger V-shaped section 25, the switch position 1 may be readily sensed by the operator. Also, by reason of the fact that the tape 45 is wider than the slot 52 in the cover 51 and is in close contact with the inside surface of the cover, dust and dirt are effectively prevented from entering the interior cavities of the switch device 10.

The above-described embodiment of slide switch has a number of advantageous features, among which are its miniature size, simplicity of design including dust and dirt seal, ease of assembly and disassembly, adaptability for use in various applications, and serviceability. The use of a standard form of contact element for all switch positions enables savings in manufacturing costs.

It will be understood that the embodiment of slide switch herein shown and described is susceptible of various modifications or changes within the terms of the appended claims.

We claim:

1. A slide switch comprising a base member of insulating material having a longitudinal groove of V- shaped cross-section and a transverse slot intersecting said groove, a pair of opposingly faced contact elements in said slot forming a V-shaped seat therebetween of larger cross-section than said groove, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on the said recessed shoulder, a projection on the contactor that extends downwardly through said longitudinal slot and carries a plurality of superposed metal balls depending therefrom, and resilient means acting on said balls, the lowermost one of said balls being biased into seated engagement in said longitudinal groove by the other of said balls and resilient means and snapped suddenly outward into bridging contact with said pair of contact elements as said contactor shifts slidably toward said pair of contact elements.

2. A slide switch according to claim 1, wherein said contactor has a bore therein normal to said longitudinal groove, wherein a cartridge is slidably mounted in said bore containing two superposed metal balls, and wherein spring means is the resilient means in said bore acts on the uppermost one of said metal balls to apply a biasing force to the said metal balls.

3. A slide switch according to claim 1, wherein a sheet-metal cover surrounds said base and cover members to hold them in superposed adjacent positions, said cover having a longitudinal slot through which a handle of said contactor extends.

4. A slide switch according to claim 1, wherein a dust shield in the form of an endless tape longitudinally surrounds said base and cover members in close contact therewith, said tape having an opening through which a handle of said contactor extends and being shifted circuitously with sliding movement of said contactor.

5. A slide switch according to claim 1, wherein said sheet-metal cover has formed integrally therewith a plurality of spaced projections serving as mounting legs for said switch.

6. A slide switch according to claim 3, wherein said base and cover members have a recess extending longitudinally therearound, and a dust shield in the form of an endless tape wider than the said longitudinal slot in said sheet-metal cover is disposed in said recess and longitudinally surrounds said base and cover member in close contact therewith, said tape having an opening through which the handle of said contactor extends and being shifted circuitously in said recess by sliding movement of said contactor.

7. A slide switch according to claim 4, wherein spring means is interposed between said tape and the said base member to maintain said tape taut and in close contact with the top of said cover member.

8. A slide switch comprising a base member of insulating material having a longitudinal groove of V- shaped cross-section, a section of said groove having an enlarged cross-section of V-shape, a transverse slot intercepting said groove in longitudinally spaced relation to said enlarged section of said groove, a pair of contact elements opposingly faced in said slot, a connector element normally biased into bridging contact with said pair of contact elements, a cover member of insulating material having a longitudinal slot and a recessed shoulder surrounding said slot, a contactor having a flat body of insulating material slidable on said recessed shoulder in said cover member and detenting means extending through said longitudinal slot and engageable with said enlarged section of said groove, said contactor being effective when the detenting means engages in the enlarged section of said groove, to engage said connector element and shift it out of bridging contact with said contact elements. I

9. A slide switch according to claim 8, wherein said connector element comprises a ribbon type spring element having a S-shaped contour, one leg of the spring element normally bridging the contact elements and adapted to be engaged and resiliently bent out of bridging relation to the contact elements by said contactor when the detenting means engages in the enlarged section of said groove.

10. A slide switch comprising a base member of insulating material having a longitudinal groove of V- shaped cross-section, a section of said groove having an enlarged cross-section of V-shape, a transverse slot in longitudinally spaced relation to said enlarged section ofsaid groove, one side of said slot being open to said groove and the other side having a ramp adjacent thereto, a pair of contact elements opposingly faced in said slot to provide a V-shaped seat, a metal ball seated in bridging relation to said pair of contact elements, means yieldingly biasing said ball into contact with said pair of contact elements, a cover member of insulating material having a longitudinal slot and a recessed shoulder surrounding said slot, a contactor having a flat body of insulating material slidable on said recessed shoulder in said cover member and detenting means engageable with said enlarged section of said groove, said contactor having a longitudinal projection which, when said detenting means engages in the enlarged section of said groove, contacts said metal ball and shifts it laterally out of the transverse slot up said ramp to disengage said contact elements.

ll. A multi-position slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a plurality of longitudinally spaced transverse slots intersecting said groove, a pair of opposingly faced contact elements forming a V-shaped seat therebetween disposed in each of said slots, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on said recessed shoulder and having a depending portion carrying a plurality of superposed metal balls yieldingly biased whereby the lowermost ball is urged into seated engagement within said longitudinal groove from which it is suddenly snapped outwardly selectively into bridging contact with certain ones of said pairs of contact elements as said contactor is shifted slidably on said recessed shoulder.

12. A multi-position slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a plurality of longitudinally spaced transverse slots intersecting said groove, a pair of opposingly faced contact elements forming a V-shaped seat therebetween disposed in each of said slots, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on said recessed shoulder and having a depending portion carrying a metal ball yieldingly biased into seated en gagement within said longitudinal groove from which it is suddenly snapped outwardly selectively into bridging contact with certain ones of said pairs of contact elements as said contactor is shifted slidably on said recessed shoulder, and a connector element normally yieldingly biased into bridging relation to a pair of said contact elements at one end of said switch, and wherein said contactor engages said connector at one extremity of travel thereof to shift said connector element out of bridging relation to said contact elements.

13. A multi-position slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a plurality of longitudinally spaced transverse slots intersecting said groove, a pair of opposingly faced contact elements forming a V-shaped seat therebetween disposed in each of said slots, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on said recessed shoulder and having a depending portion carrying a metal ball yieldingly biased into seated engagement within said longitudinal groove from which it is suddenly snapped outwardly selectively into bridging contact with certain ones of said pairs of contact elements as said contactor is shifted slidably on said recessed shoulder, and wherein one of said transverse slots has a ramp at one side thereof and a ball is yieldingly biased into bridging contact with the pair of contact elements contained in said one transverse slot, and wherein said contactor has a longitudinal projection which engages said ball to shift it laterally up said ramp to disconnect the. said pair of contact elements.

. UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N 3,757,060 D t September 4, 1973 ln nwfl JOSEPH N. IANUZZI and DONALD A. MOHNEY It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 41, "means" should be --+members Signed andsealedthis 1st day of January 1974.

(SEAL). Attest:

EDWARD M.FLETCHER,JR

I RENE D. TEGTMEYER Attestlng Offlce r Actlng Commissioner of Patents FORM PO-wSO (10-69) uscoMM-Dc wanw u.s. sovzlmmzu Mumps orrlcz: I"! 0-3664,

V UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent o- 3,757,060 Dated September 4, 1973 fls) JOSEPH N. IANUZZI and DONALD A. MOHNEY It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 41, "means" should be --members-.

Signed and sealed this 1st day of January 1974.

(SEAL) Attest:

EDWARD M. FLETCHER JR RENE D. TEGTMEYER Attestlng Officer Acting Commissioner of Patents USCOMM-DC 6O376-P69 u.s. GOVERNMENT Pnlghfme orrlcz I"! o-asi-su,

F ORM P04 050 (10-69) 

1. A slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section and a transverse slot intersecting said groove, a pair of opposingly faced contact elements in said slot forming a V-shaped seat therebetween of larger cross-section than said groove, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on the said recessed shoulder, a projection on the contactor that extends downwardly through said longitudinal slot and carries a plurality of superposed metal balls depending therefrom, and resilient means acting on said balls, the lowermost one of said balls being biased into seated engagement in said longitudinal groove by the other of said balls and resilient means and snapped suddenly outward into bridging contact with said pair of contact elements as said contactor shifts slidably toward said pair of contact elements.
 2. A slide switch according to claim 1, wherein said contactor has a bore therein normal to said longitudinal groove, wherein a cartridge is slidably mounted in said bore containing two superposed metal balls, and wherein spring means is the resilient means in said bore acts on the uppermost one of said metal balls to apply a biasing force to the said metal balls.
 3. A slide switch according to claim 1, wherein a sheet-metal cover surrounds said base and cover members to hold them in superposed adjacent positions, said cover having a Longitudinal slot through which a handle of said contactor extends.
 4. A slide switch according to claim 1, wherein a dust shield in the form of an endless tape longitudinally surrounds said base and cover members in close contact therewith, said tape having an opening through which a handle of said contactor extends and being shifted circuitously with sliding movement of said contactor.
 5. A slide switch according to claim 1, wherein said sheet-metal cover has formed integrally therewith a plurality of spaced projections serving as mounting legs for said switch.
 6. A slide switch according to claim 3, wherein said base and cover members have a recess extending longitudinally therearound, and a dust shield in the form of an endless tape wider than the said longitudinal slot in said sheet-metal cover is disposed in said recess and longitudinally surrounds said base and cover member in close contact therewith, said tape having an opening through which the handle of said contactor extends and being shifted circuitously in said recess by sliding movement of said contactor.
 7. A slide switch according to claim 4, wherein spring means is interposed between said tape and the said base member to maintain said tape taut and in close contact with the top of said cover member.
 8. A slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a section of said groove having an enlarged cross-section of V-shape, a transverse slot intercepting said groove in longitudinally spaced relation to said enlarged section of said groove, a pair of contact elements opposingly faced in said slot, a connector element normally biased into bridging contact with said pair of contact elements, a cover member of insulating material having a longitudinal slot and a recessed shoulder surrounding said slot, a contactor having a flat body of insulating material slidable on said recessed shoulder in said cover member and detenting means extending through said longitudinal slot and engageable with said enlarged section of said groove, said contactor being effective when the detenting means engages in the enlarged section of said groove, to engage said connector element and shift it out of bridging contact with said contact elements.
 9. A slide switch according to claim 8, wherein said connector element comprises a ribbon type spring element having a S-shaped contour, one leg of the spring element normally bridging the contact elements and adapted to be engaged and resiliently bent out of bridging relation to the contact elements by said contactor when the detenting means engages in the enlarged section of said groove.
 10. A slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a section of said groove having an enlarged cross-section of V-shape, a transverse slot in longitudinally spaced relation to said enlarged section of said groove, one side of said slot being open to said groove and the other side having a ramp adjacent thereto, a pair of contact elements opposingly faced in said slot to provide a V-shaped seat, a metal ball seated in bridging relation to said pair of contact elements, means yieldingly biasing said ball into contact with said pair of contact elements, a cover member of insulating material having a longitudinal slot and a recessed shoulder surrounding said slot, a contactor having a flat body of insulating material slidable on said recessed shoulder in said cover member and detenting means engageable with said enlarged section of said groove, said contactor having a longitudinal projection which, when said detenting means engages in the enlarged section of said groove, contacts said metal ball and shifts it laterally out of the transverse slot up said ramp to disengage said contact elements.
 11. A multi-position slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a pluraliTy of longitudinally spaced transverse slots intersecting said groove, a pair of opposingly faced contact elements forming a V-shaped seat therebetween disposed in each of said slots, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on said recessed shoulder and having a depending portion carrying a plurality of superposed metal balls yieldingly biased whereby the lowermost ball is urged into seated engagement within said longitudinal groove from which it is suddenly snapped outwardly selectively into bridging contact with certain ones of said pairs of contact elements as said contactor is shifted slidably on said recessed shoulder.
 12. A multi-position slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a plurality of longitudinally spaced transverse slots intersecting said groove, a pair of opposingly faced contact elements forming a V-shaped seat therebetween disposed in each of said slots, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on said recessed shoulder and having a depending portion carrying a metal ball yieldingly biased into seated engagement within said longitudinal groove from which it is suddenly snapped outwardly selectively into bridging contact with certain ones of said pairs of contact elements as said contactor is shifted slidably on said recessed shoulder, and a connector element normally yieldingly biased into bridging relation to a pair of said contact elements at one end of said switch, and wherein said contactor engages said connector at one extremity of travel thereof to shift said connector element out of bridging relation to said contact elements.
 13. A multi-position slide switch comprising a base member of insulating material having a longitudinal groove of V-shaped cross-section, a plurality of longitudinally spaced transverse slots intersecting said groove, a pair of opposingly faced contact elements forming a V-shaped seat therebetween disposed in each of said slots, a cover member of insulating material secured to said base member and having a longitudinal slot therethrough surrounded by a recessed shoulder, a contactor having a flat body of insulating material slidable on said recessed shoulder and having a depending portion carrying a metal ball yieldingly biased into seated engagement within said longitudinal groove from which it is suddenly snapped outwardly selectively into bridging contact with certain ones of said pairs of contact elements as said contactor is shifted slidably on said recessed shoulder, and wherein one of said transverse slots has a ramp at one side thereof and a ball is yieldingly biased into bridging contact with the pair of contact elements contained in said one transverse slot, and wherein said contactor has a longitudinal projection which engages said ball to shift it laterally up said ramp to disconnect the said pair of contact elements. 